Means for lubricating sheet metal during rolling



April 26, 1955 MEANS FOR Filed March 4, 1952 G. E. TURPIN 2,707,098 LUBRICATIDNG SHEET METAL DURING ROLLING 2 Shegtsi-Sheet 1 IN VE N TOR 1 ATTORNEYS United States Patent tiice 2,707,098 MEANS non LunnIcATIuG SHEET METAL DURING ROLLING Geollrey Edgar Turpin, Slretty, Swansea, Wales, assignor to The Steel (Iompany of Wales Limited, Port Talbot, W ales Application March 4, 1952, Serial No. 274,789

Qlaims priority, application Great Britain November 27, 1951 4 Claims. (Cl. 261-44) This invention relates to means for atomising liquids, particularly for lubricating sheet metal during rolhng.

It is an object of the invention to provide an improved means which is more economical of oil and is easier to control than methods now employed. Palm oil is used as a strip lubricant during the processes of cold rolling and it is essential that it be applied uniformly and that the amount of palm oil used be a minimum and yet sufficient at all speeds of rolling. It is important that no more oil than is really required should be used, because this oil mixes with the roll coolant water and rapidly settles out, making it necessary to re-claim and refine the oil before it can be used again.

A further object of the invention is to provide an mproved form and construction of apparatus for apply ng a thin, even film of lubricant to the sheet metal during rolling. The improved apparatus is moreover applicable for use where atomised liquids are required in other manufacturing processes, such for instance in the application of oil to woo-l, or in the spraying of paint and like coating compositions.

Yet another object of the invention is to provide a form of apparatus which is adapted to produce a fine spray from substances which are of a relatively viscous nature, such as the palm oil normally used for lubricating sheet metal during rolling into thin plates and strip.

According to the invention a means for producing a spray of liquid, such as oil, in suspension in a stream of gas for treating a surface or material, consists in passing the gas through a conduit, heating said gas therein, then injecting the liquid into said heated gas, and then directing the gas and atomised liquid mixture against the surface to be treated. Preferably the gas is passed through a conduit in a heat exchanger, and the liquid is injected at a position part way along said conduit, the heat exchanger acting to heat the gas prior to and subsequent to the injection.

Further according to the invention, a means for lubrieating sheet metal during rolling consists in directing against it a stream of compressed gas carrying globules of oil. Thus lubrication may be effected by passing compressed air in a stream along a heated conduit, injecting oil into said stream within the conduit so that the oil is atomised, and then delivering the oil-charged compressed air against the surface to be lubricated.

There is further provided according to the invention an apparatus for producing a spray of atomised liquid such as oil, comprising a conduit, inlet means at the com mencement of the conduit for connection to a supply of compressed gas, delivery means at the termination of said conduit, heating means for raising the temperature of the gas as it passes along the conduit, and liquid injection means intermediate the ends of said conduit for introducing the said liquid into the conduit, which liquid is carried along by the current of heated gas and is discharged with said gas as an atomised suspension, through the delivery means.

The invention will now be described in conjunction with the accompanying drawings, in which:

Figure 1 is a fragmentary front elevation of a sheet metal rolling mill having the improved lubricating apparatus;

Figure 2 is a longitudinal sectional elevation of the heat exchanger and liquid injection unit, drawn to an enlarged scale;

Figure 3 is a transverse sectional elevation taken on the line 3-3 of Figure 2; and

Figure 4 is a diagrammatic side elevation of a system for automatically regulating the supply of lubricant in accordance with the roll speed.

The rolling mill shown in Figure l is of the usual construction and is of the four high design having a pair of work rolls, namely, an upper roll 10 and a lower roll 11. These are mounted pivotally in the columns 12, 13 of the mill frame and are supported against the rolling pressure by upper and lower backing rolls l4 and 15 respectively. The sheet metal being rolled passes horizontally between the work rolls 10 and Ill and is indicated at 16. in order to cool the rolls and the sheet metal, these are sprayed with water, but this spraying equipment is not shown in the drawings.

The sheet metal 16 is lubricated by spraying with oil, such as palm oil, before it enters between the rolls 10 and ll. The improved spraying apparatus for performing this function is shown in Figure 1 and comprises mainly a combined heat exchanger and oil injection unit indicated generally at 17. This uses steam as heating fluid and has a steam inlet 18 connected to a steam supply pipe 19, while its opposite end has an outlet connection 2d coupled to an exhaust pipe 21. The unit 17 is fed with oil through an oil inlet 22, this being connected by a pipe 23 with a steam-heated circulating system 24 through which palm oil is pumped in order to avoid clogging, for the oil would freeze at atmospheric temperature. A thermometer 25 shows the temperature in the circulating system. in order to control the flow of oil to the unit 17 a cock 27 is provided in the pipe 23 and is intended merely for turning the supply on and off; a valve 26 also in the pipe 23 is used to regulate the sup ply and may be adjusted manually from time to time. The working gas which is used to form and carry the oil spray is compressed air, this being fed into a compressed air inlet 28 connected by a pipe 29 from a compressed air main. Again, a cock 31 is used for turning the supply on and off, while a valve 3% can be set manually to regulate the flow. From. the left-hand end of the unit 17 a discharge outlet 32 leads into a pipe 33 connected by a flexible pipe 34 to a manifold 35 from which a plurality of open ended pipes 36 lead and are directed downwards towards the top surface of the sheet 16 about to be rolled. Heated air carrying oil globules as a fine suspension is discharged under pressure through the outlet 32 and this mixture thus blows downwards upon the sheet 16 causing the globules to be deposited thereon and to be spread into a thin film by the air stream. A branch pipe 37 leads from the pipe 33 to a lower manifold 38 feeding a number of pipes 3%, the open ends of which are directed upwards so that the air and oil mixture issuing from their upwardly-directed open ends impinges against the underneath surface of the sheet 16. A cock 40 is provided in the pipe 37 to enable the flow through the pipes 39 to be regulated. A pressure gauge 41 is fitted to a socket 42 on the unit 17 and shows the air pressure therein. The delivery pipes 36, 39 are adjustably mounted and they can if desired be directed to deliver the oilair mixture on to the surfaces of the work rollers 10, 11.

The internal construction of the unit 17 is shown in detail in Figures 2 and 3. It comprises an inner barrel 45 disposed concentrically within an intermediate tube 46, this being surrounded by an outer tube 47. A bush 48 welded to the left-hand end of the barrel 45 serves to connect the bore 49 of said barrel to the delivery outlet 32 for the air-oil mixture. A flange 50 is welded into the end of the intermediate tube 46 so as to close the annular chamber 51 inside the tube 46. At the opposite end a stepped plug member 52 has a spigot 53 which is welded into the bore of the barrel 45', an annular step 54 which is Welded to the intermediate tube 46 to close the right-hand end of the chamber 51, and an outer part 55 which is welded into the outer tube 47. Thus the part 55 closes the end of an outer annular chamber 56 between the tubes 46 and 47, the left-hand end of this chamber being closed by a ring 57 welded in position.

The stepped plug 52 is formed with a cylindrical axial projection 58 to which the oil inlet 22 is welded, this inlet leading into an annular groove 59 formed around a screwthreaded bore es, coaxial with a smaller diameter bore 61. An oil nozzle member 62 has a body portion 63 screw-threaded into the bore and a lock nut 64; it is formed with an axial passage 65 which is plugged at 66 but communicates with the oil inlet 22 by way of radial passages 67 and the annular groove 59. The inner end of the nozzle member 62 projects into a cavity 68 formed within the plug member 52, said cavity 63 being shaped like a venturi passage where indicated at 69; the external diameter of the nozzle member 62 is reduced at this part of its length so as to form a divergent end portion 70, the actual end surface 71 being concave, with a calibrated nozzle bore 72.

An annular cap 73 recessed at 74 is fitted upon the projection 58 and welded in position so that the recess 74- communicates with a number of drilled passages 75 lead ing into the annular chamber 51; a passage 76 leads from the recess 74 to the steam outlet 29. Similarly at the opposite end of the unit the steam inlet 18 leads into the chamber 51 by way of a passage 77, said chamber thus forming a steam jacket bounded on its inside by the bore 49 of the barrel 45, and on its outside by the annular chamber 56, herein termed the pre-heating chamber.

The compressed air inlet 23 leads through a hole 78 in the left-hand end of the outer tube 47, the compressed air flowing through a heating duct comprising the preheating chamber 55, a number of radial transfer passages 79 in the plug member 52 (see Figure 3), the cavity 68 and the bore 49 of the inner barrel. The outside of the intermediate tube 46 is surrounded by a wire helix 86 which is welded in position and greatly improves the heat transfer efliciency by providing an enlarged surface upon the outside of the steam jacket and also by causing turbulent flow in the air within the pre-heating chamber 56. In the bore 49 the cross-sectional area of the passage is substantially reduced by a core member 81 comprising a cylindrical rod which is held coaxially within the bore 49 by sets of radial arms 82 and 83 at its ends; the arms 82 are welded to the barrel 45 to locate the core member axially, but the arms 83 are left free to allow for difierential expansion. The core member 81 has a frustoconical end part 84 spaced a short distance from the end face 71 of the oil nozzle, through which latter the oil continuously streams while the device is in use so that the oil is broken up into fine globules, the oil-air mixture then being compelled to flow along the relatively thin annular space 49a lying contiguous to the steam-heated inner barrel. Thus the mixture is further heated to make the oil exceedingly fluid and cause it to be thoroughly broken up or atomised by the swift air current. The far end of said core member is conically tapered as shown at 85 to slow down the stream before it flows into the discharge outlet 32.

In practice a dense oil mist is delivered under pressure through the outlet 32 and is directed by the open-ended pipes 36, 39 against the upper and lower surfaces of the sheet 16, so that the oil is deposited thereon (possibly aided by some condensation of oil vapour), thus producing a very thin well-distributed film which is found to give an excellent rolling eiiiciency using the minimum quantity of oil.

The actual rate at which oil is supplied can be regulated by adjustment of the valve 26 to suit the current working conditions. if desired, however, an automatic device can be provided to regulate the oil supply in accordance with the actual rolling speed, and one suitable device is shown in Figure 4. The supply of oil through the pipe 23 is controlled by a valve 26a comprising a housing 90 having a freely rotatable plug member 91 having a diametral bore. A spindle 92 on the plug has a radial arm 93 to the outer end of which an arcuate iron core member 94- is secured so as to be concentric with the axis of the plug 91. An electric solenoid coil 95 is mounted with its bore in line with the core member 94, the core member being just free of the coil when the valve 26a is in its closed position as shown. It is normally urged towards this closed position by a light spring 96 or other means, but when the solenoid coil is energised the core member is drawn into it by magnetic force, thus opening the valve 26a to an extent dependent upon the strength of the electric current. There are many ways in which the solenoid coil 95 can be fed with a current which varies in accordance with the rolling speed and/or other working factors, but in the arrangement shown a small dynamo 97 is driven by a belt or chain 98 from one of the roll spindles, indicated at 99, so that its speed is always proportional to the roll speed. Wires 160 connect the dynarno 97 to the solenoid coil 95.

It will be understood that various other modifications may be made to suit requirements. Furthermore, the improved apparatus for atomising oil by means of heated compressed air may be used for various purposes other than in sheet metal rolling. For example, olive oil may he introduced into the stream of compressed air and the resulting oil mist used for treating raw wool for manufacturing purposes. Moreover, other liquids may be used in the same way, and also gases other than compressed air may be used to atomise the liquid and blow it as a mist on to the surface or material to be treated.

What I claim is:

1. An apparatus for producing a spray of atomised liquid such as heated palm oil, comprising an inner tube, an oil injection nozzle disposed within one end of said inner tube, spray delivery means at the other end of said inner tube, an intermediate tube surrounding the inner tube but spaced therefrom to form an intermediate annular heating jac et, means for passing heating fluid along said heating jacket, an outer tube surrounding the intermediate tube but spaced therefrom to form an outer annular chamber, which is of small radial thickness and is shorter in axial length than the heating jacket, said outer annular chamber being carried wholly upon the outside of the intermediate tube, means for feeding compressed air into the outer annular chamber at that end thereof adjacent the delivery end of the inner tube, transfer conduit means forming a connection for compressed air extending from the outer annular chamber directly into the inner tube at the inlet end thereof, and fins anchored to the outside of the intermediate tube and extending outwards within the outer annular chamber to increase the transmission of heat to the compressed air before it reaches the transfer conduit means.

2. An apparatus according to claim 1, in which the fins comprise a helical Wire disposed upon the outside of the intermediate tube and welded thereto.

3. An apparatus according to claim 1, having a core member disposed within the bore of the inner tube, and means supporting said core member coaxially with respect to said tube, leaving a passage with an annular cross section and a narrow radial width, the annular passage being bounded on its outside periphery by the inner tube which forms the inside wall of the heating jacket.

4. An apparatus for producing a spray of atomised liquid, such as heated palm oil, comprising an inner tube, a stepped plug fitted into one end of said inner tube, an oil injection nozzle fitted into said stepped plug and delivering into'ht he bore of said inner tube, spray delivery means at theotherend of said inner tube, an intermediate tube surrounding the inner tube but spaced therefrom to form andntermediate annular heating jacket, said intermediate tube being fitted on firthe stepped plug and maintained thereby concentric with theinner tube, means for passing' heating fluid along .said heating jacket, an outer tube surrounding the intermediate tube butspgced therefrom to fornran outer annular chamber, the oaitep tube being fitted upon the. stepped plug, which latter maintains it concentric with thhnigajiid intermediate tubes, the a outer tube being shorter in jacket, and said outer annulafclgmber being carried wholly upon the outside of the intermeQate tube. means for feeding compressed air into the outer annular chamher at that end thereof adjacent the dclivcry end of the inner tube, a plurality of transfer passages formed in the stepped plug to form a connection for compressed air extending from the outer annular chamber directly into the inner tube at the inlet end thereof, and fins anchored to the outside of the intermediate tube and extending outwards within the outer annular chamber to increase the transmission of heat to the compressed air before it reaches the transfer conduit means.

References Cited in the file of this patent UNITED STATES PATENTS rial length than the-heating 

